Dispersants containing terminal acidic groups, such as, phosphates and sulphates are known, and are generally, prepared by reaction of a hydroxy ended polymer chain with phosphorus pentoxide, phosphorus oxychloride, polyphosphoric acid or sulphuric acid. The dispersant polymer chains are often derived from polyester or polyalkoxylate chains containing terminal hydroxyl groups. Dispersants known in the art containing terminal acidic groups are suitable for a polar medium, such as, water, ketones, esters and the like. However, it would be advantageous to utilise the dispersant properties of compounds containing terminal acidic groups in both a polar and a non-polar organic medium. The present invention provides such a dispersant and compositions thereof.
U.S. Pat. No. 5,300,255 discloses dispersants containing a polyester derived from a hydroxycarboxylic acid with not more than 8 carbon atoms reacted with phosphorus pentoxide or sulphuric acid. The dispersants are effective in polar medium such as aromatic solvents and plastics.
U.S. Pat. No. 5,130,463 discloses dispersants of a polyether/polyester derived from ε-caprolactone reacted with polyphosphoric acid. The dispersants are effective in more polar medium, such as, ketones and esters.
U.S. Pat. No. 5,879,445 discloses a process for fluidizing an aqueous suspension of mineral particles with compounds based on polyether amine methylene phosphonates, i.e., water based Jeffamine mono- and bis-methylene phosphonates. The polyether chain consists mainly of ethylene oxide (EO) and propylene oxide (PO).
European Patent Application 961803 discloses similar compounds to U.S. Pat. No. 5,879,445, except EP961803 further discloses the use of polyether amine methylene phosphonates as dispersants for dispersing carbon black in an aqueous medium.